Method of building roofs for liquid-storage tanks and gas holders



Oct. l5, 1929 J.. H. wlGGlNs METHOD OFVBUILDINGv ROOFS FOR LIQUIDSTORAGE TANKS AND GAS HOLDERS Filed July 5, 192'/` Patented Oct. 1929UNITEDUSTAIES PATENT OFFICE JOHN H. WIGGINS, or 'BARTLESVILLIL OKLAHOMA-`IEET-HOD BUILDING ROOFS FOR LIQUID-STORAGE TANKS AND GAS HOLDERSApplication led July 5,l 1927. Serial No. 203,589.

under certain conditions, thus increasing' the volume of the vapor spacein the upper porT tion of the tank. One method that can be used toconstruct such a tank roof is to connect the roof plates to eachotherand to the side wall of the tank when said plates are resting upon adownwardly concave-shaped supporting structure that sustains the roofwhen it is in its normal, Idepressed position, l but one disadvantage ofsuch' a. method is that the roof. plates wrinkle abnormally when theroof reaches a horizontal position in passing from its depressedposition into its raised position, or vice versa.

Thev object of my present inventionis to provide a method ofconstructing a tank roof of the kind referred to, that eliminateswrinkling or reduces. wrinkling of the roof plates when the roofispassing from its normal, depressed position into its raised orinverted position, or vice versa, with'- y out, howeverweakening theroof or causing the plates or the joints of the roof to be subjected to.abnormal strains when the roof is in its raised position. lTo this endI propose to connect the roof plates to each other and to the side wallof the tank while said platcs arev sustained in a substantiallyhorizontal position at a point above the depressed or normal position ofthe roof,

and thereafter permit the cent-ral portion of l the root' to deflectsufficiently to put the plates and the joints of the roof under sometension, and linally come to rest in its normal position on a downwardlyconcave-shaped supporting structure. Preferably, the struc? ture that isused to support the roof in its normal position is used to support theroof plates while they are -being fastened to ether and attached to theside wall of the tan and at the completion of said operation the centralportion of said supporting structure is depressed suflicientlyto'produee a downwardly concave-shaped support for the roof.' In con-vstructing a roof that yhas only a relatively 55 slight movement upwardlyand downwardly from a horizontal plane intermediate the normal andinverted positions of the roof, the

supporting structure on which the roof plates are sustained during theoperation of connecting them together is arranged substantiallyhorizontal in close proximity to said horizontal plane, but inconstructing a roof that has a relatively great movement upwardlyanddownwardly fromy said intermediate horizontal plane, the supportingstructure on which the roofplates are sustained while they are beingconnected together is arranged so that it will be inclined downwardlyslightly for example, with adrop of, say, one foot at the center of thestructure, and after the roof plates have been lconnected together andattachedto the side wall of the tank, the central portion of saidsupporting structure is dropped another foot. Accordingly, when the roofis in its normal depressed position the central yportion of the roofwill be two feet below the horizontal plane at the top edge 'of sidewall of the tank, and when the roof flexes upwardly into its inso vertedor elevated position, the central portion of the roof will be two feetabove said horizontal plane. By constructing the roof in this manner Iutilize the tension of,` the roof plates solely or in conjunction withsome 85 eXtra metal that is built into the roof due to fasteningl theroof plates together while they are sustained on a slightly dishedsupport, to permit the roof to flex upwardly into its upwardlyconcave-shape without liability of straining the roof, and as there isonly a small amount of excess metalv in the roof, the roof plates willnot wrinkle abnormally while the roof is passing through theintermediate horizontal plane in moving from its depressed to itselevated position, or 'vice versa.

Figure 1 ofthe drawings is a vertical transverse sectional view,illustrating my improved method of constructing the top or roof of asupporting structure for thereof plates'in Athe position it occupieswhen the roof plates are beingconnected together and attachedto the sidewall of the tank; and

' Figure 2 is avei'tical transverse sectional View, 'showing :thecentral portion of said structurevdropped at the completion of theoperation of connecting the roof plates together', soas to serve as asupport for the roof when it is in its normal ldepressed position.

Referring to the drawings, A designates the side wall ofla liquidstorage tank that is equipped with a roof or top B that is of downwardlyconcave-shape when it is in its normal or depressed position, and whichis capable of, flexing upwardly into an upwardly concave shape so as toincrease the volume of the vapor s ace above the surface of the liquidin the tan Said .rooi' is preferably constructed from metal plates thatare joined together and attached tothe side wall of the tank in such away as to form a gas-tight closurev for the tank, and a relief valve ismounted. on the roof so as `to relieve or reduce the internal pressureof the` tank when the roof approaches its extreme elevated position orinverted position, as described in my pending application previouslyreferred to.`

In building the roof I prefer to attach the roof plates to each otherand to the side wall ofthe tank while said plates are sustained on asupporting structure, designated as an entirety by the referencecharacter C, that is arranged inside of the tank in asubstantiallylhorizontal position in close proximity to a horizontal plane at the topedge of the ,Side wall of the tank, as shown in Figure 1. Said suporting structure is herein illustrated as being sustained by bracketsor lateral projections 1 on the side Wall of the tank, and byvertically-disposed uprights lformed by posts 3 of different lengthswhich are in turn mounted on removable sup orts- 4 of different lengthsthat rest upon t e bottom of the tank, thel posts 3 gradually decreasingin length or height from the side wall of the tank towards the center ofthe tank and the removable supports 4 increasing gradually in heightfrom the side wall of the tank towards the center. v

At the completion of the operation of oining the roof plates toge'therand attac ing' them to the side wall ofthe tank, the supports 4 atthelower end'of the posts 3 are removed so as to permit the posts 3 to restdirectly upon the bottom of the tank, thus (causing the central portionof the supporting structure C to drop downwardly as shown in Figure 2,and assume the shape of a downwardl concaved support' on which the roofrests w ien it is in its normal depressed position.

The position in which the supporting structure C is arranged during theoperation of deflection of the roof if the roof was sustainedA solely bythe sidewall of the tank, as this might result in straining the jointsbetween the Vroof plates and between the peripheral edge of the roof andthe side wall of the tank. Various other means than the posts 3 andremovable supports 4 .can be used to sustain the supporting structure C,and if desired, the removable supports 4 ca'n be arranged between theupper ends of said posts and the supporting structure C, instead vofbetween the lower endsof said posts and the bottom of the tank. v i,

Having thus described my invention, what I claim as new'and desire tosecure by Letters Patent is:

1. A method of constructing a tank roof that is attached at itsperipheral edge to the side wall of the tank, and which is capable offlexing upwardly and downwardly from a horizontal plane intermediate thetwo eX- treme positions of the roof, consisting in connecting the roofmembers to each other and attaching them to the side wall of the tankwhile said roof members are arranged at a point above the normaldepressed position of the roof, and at the completion of said operationpermitting the roof to assume a downwardly concave-shape.

2. A method of constructing a tank roof that is attached at itsperipheral edge to the side wall of the tank, and which is capable offlexing upwardly and downwardlyyfrom a horizontal plane intermediate thetwo extreme positions of the roof, consisting in conf n necting the roofmembers to each other and attaching them to the side wall ofthe tankwhile said roof members are arranged vat a point above the normaldepressed position of the roof, and at the completion of said operationpermitting the central portion ot' the roof to deflect a distance lesst-han the maximum deflection of the roof if it were supported solely bythe side wall. of the tank.

3. A method of constructing a tank roof that is attached at itsperipheral edge to the side wall of the tank, and which is-capable offlexing upwardly and downwardly from a horizontal plane intermediate thetwo Lex'- treme-pqsitions of the roof, consisting in connectinor theroof members to each other and attachmg them to the side wall ofthe'tank by .thereafter lowering the central portionof' said supportingstructure so as vto cause it to assume the shape of adownwardly-conceived support on which the roof rests when it is in itsnormal, depressed position.

4. A method of 'constructing a tank roof that is attached at itsperipheral edge to the 5 side wall of the tank, and which is capable offlexing upwardly and downwardly from a horizontal plane intermediate thetwo extreme positions of the roof, consisting in arranging asubstantially horizontally-disposed supporting structureinside of thetank, adjacent the upper edge of same, on uprights, mounting metalplates on said structure and connecting said plates to each other and tothe side wall of the tank, and thereafter changing the length of saiduprights in such a way as' to cause the supporting structure and theroof thereon to assume a downwardly concave-shape.

5. A method of constructing a tank roof i which is adapted to flexupwardly and down- -wardly above an intermediate horizontal plane,consisting in joining metal plates together and attaching them to theside wall of the tank so as to form a gas-tight roof, sustaining theplates during the above described operation by a supporting structureinside of the tank, and subsequently changing the shape of saidstructure-so as to cause the central portion of the roof to deflectsuliciently to put some tension on the plates and joints of the roof andthereafter come to rest in its normal downwardly deflected condition onsaid structure.

6. A method of constructin a tank roof that is adapted to Hex upwar lyand downwardly from an-intermediate horizontal plane when the tank is innormal use, consisting -in joining metal plates together and attachingthem` to the side wall of the tank so as to form .a tight top for thetank, sustaining the plates during the above operation by av supportingstructure which is of different shape than the roof when said roof is ineither of its extreme positions, and at the completion of said operationconverting said supporting structure into a downwardly concaved supporton which the -roof rests when it is in its normal, downwardly-deflectedcondition.

JOHN H. WIGGINS.

